A. Field of Invention
This invention relates to the field of high pressure, high speed rotary valves. More specifically, this invention comprises a rotary valve with multiple flow paths that is capable of valve actuation cycle frequencies in excess of 2000 Hz at inlet pressures in excess of 600 psi.
B. Description of Related Art
Rotary valves are used in industry for a number of applications like controlling the flow of liquids to molds, regulating the flow of hydraulic fluids to control various machine functions, industrial process control, and controlling fluids which are directed against work pieces. The vast majority of these applications are conducted at low fluid pressures and at either low rotational speeds or through an indexed movement. These applications have been addressed through application of various known fluid regulation valve applications including gate valve, ball valves, butterfly valves, rotating shafts with various void designs and configurations, solenoid actuated valves of various designs, and valves designed with disks with multiple holes to redirect flow streams. These applications are generally acceptable for low speed, low pressure processes, but are not suitable for high speed, high pressure processes.
For example, solenoid valves are effective for regulating fluid flow up to a frequency of approximately 300 Hz at a pressure of up to 200 psi. These limitations are primarily due to the physical design of the solenoid which relies upon the reciprocating motion of magnetic contacts and is therefore subject to significant acceleration and deceleration forces, particularly at higher frequencies. These forces, the resulting jarring action, and the frictional heat generated make these type valves subject to failure at high frequencies of actuation.
Rotary valves employing multiple outlets have been used at frequencies up to 1000 Hz in applications where a low pressure differential between valve inlet and outlet ports is desired. These valves, however, are large and complex and necessarily have significant physical space requirements for the valve and for the appurtenant inlet and outlet piping.
Other methods of regulating flow force the fluid to travel through various tortuous paths, changing directions prior to exiting the device. Such a method of turning and returning the flow stream results in time delays in the output stream, significant head loss, and can be quite mechanically complicated.
Information relevant to attempts to address these problems can be found in U.S. Pat. Nos. 4,986,307, 4,345,228, 5,913,329, 6,269,838, 6,253,778, 5,988,586, 5,787,928, 5,758,689, 5,524,863, 5,305,986, 5,273,072, 5,255,715, 5,048,630, 4,658,859, 4,577,830, 4,231,545, 4,212,321, 4,177,834, 4,113,228, 3,941,351, 3,906,975, 3,774,634, 2,312,941, and 2,749,941. However, each one of these references suffers from one or more of the following disadvantages:                1. The valve actuation cycle speed (frequency) of the valve is too low;        2. The valve is large and physically complex;        3. The valve creates significant head loss;        4. The valve cannot satisfactorily operate at high inlet pressures; or        5. The valve cannot create the necessary frequency or amplitude of flow perturbation.        
For the foregoing reasons, there is a need for a high-speed, high pressure rotary valve for controlling the flow of a fluid to produce high frequency fluid pulses or perturbations. Further, there is a need for such a valve which is relatively simple in design, compact in size, compatible with standardized piping systems, and suitable for high pressure applications with minimal head loss through the valve. Such a valve may be used in applications such as creating aerosols of liquids and gases (e.g., carburetion of fuels, pesticide application, paint spraying), fuel injection for engine systems, and as part of active noise cancellation systems for supersonic jet engines and other high energy noise production systems.